We introduce a statistical data model and an associated optimization-based clustering algorithm which allows data vectors to belong to zero, one or several ''parent'' clusters. For each data vector the algorithm makes a discrete decision among these alternatives. Thus, a recursive version of this algorithm would place data clusters in a Directed Acyclic Graph rather than a tree. We test the algorithm with synthetic data generated according to the statistical data model. We also illustrate the... Topics: SYSTEMS ENGINEERING, FEASIBILITY, PROCEDURES, EXHAUSTING, ALGORITHMS, MODELS
An experimental apparatus was designed and used to measure the bidirectional reflectance of zinc oxide in the spectrum 0.25 to 2.5 microns. The nonspecular reflectance is essentially Lambert for wavelengths above 0.40 microns with the most deviation occuring for large source zenith angles. Below 0.400 microns the nonspecular reflectance is greater than Lambert in all directions and is greatest in the forward and backscatter directions. The ratio of the specular component to the nonspecular... Topics: CONFERENCES, SYSTEMS ENGINEERING, CONTROL BOARDS, TAPE RECORDERS
byInstitution of Mechanical Engineers (Great Britain)
Book digitized by Google from the library of New York Public Library and uploaded to the Internet Archive by user tpb. ( 1 reviews ) Topics: Mechanical engineering, Automatic control, Systems engineering Source: http://books.google.com/books?id=z2EAAAAAMAAJ&oe=UTF-8
byFasanella, Edwin L.; Jackson, Karen E.; Lyle, Karen H.; Spellman, Regina L
A study was performed to examine the influence of varying mesh density on an LS-DYNA simulation of a rectangular-shaped foam projectile impacting the space shuttle leading edge Panel 6. The shuttle leading-edge panels are fabricated of reinforced carbon-carbon (RCC) material. During the study, nine cases were executed with all possible combinations of coarse, baseline, and fine meshes of the foam and panel. For each simulation, the same material properties and impact conditions were specified... Topics: SYSTEMS ENGINEERING, SAFETY FACTORS, ACCIDENTS, MATHEMATICAL MODELS
Modern systems such as fly-by-wire aircraft, nuclear power plants, manufacturing facilities, battlefields, etc., are all examples of highly connected network enabled systems. Many of these systems are also mission critical and need to be monitored round the clock. Such systems typically consist of embedded sensors in networked subsystems that can transmit data to central (or remote) monitoring stations. Moreover, many legacy are safety systems were originally not designed for real-time onboard... Topics: CERTIFICATION, FUEL PUMPS, TURBINE PUMPS, SYSTEMS ENGINEERING
Support was extended to the Burst and Transient Source Experiment (BATSE) which detects sources by looking for time variability, either intrinsic to a source (such as gamma ray bursts or pulsars) or induced by earth occultation. The support was in the form of testing, calibration, and data analysis software developments. The BATSE Spectral Analysis Software (BSAS) was successfully developed. An effort was led to develop matrices suitable for use with the BSAS spectral deconvolution algorithms. Topics: COST ANALYSIS, REDUNDANCY, RELIABILITY ANALYSIS, SYSTEMS ENGINEERING, COST REDUCTION, OPTIMIZATION
The IUE and optical spectral data on a supernova remnant in M33 was combined in order to determine the abundance of carbon in the interstellar gas of M33. New shock model calculations were used to guide the interpretation and a substantially lower value of the ratio c/o than was assumed previously for M33 may be necessary to explain the data. However, some inconsistencies in the observed and predicted line intensities indicate that the spectra may be partly contaminated by H II region emission... Topics: COMPLEX SYSTEMS, OPTIMIZATION, SYSTEMS ENGINEERING, SENSITIVITY, SYSTEMS ANALYSIS
Unsteady aerodynamic models based on windtunnel forced oscillation test data and analyzed with a fuzzy logic algorithm arc incorporated into an F-16XL flight simulation code. The reduced frequency needed in the unsteady models is numerically calculated by using a limited prior time history of state variables in a least-square sense. Numerical examples arc presented to show the accuracy of the calculated reduced frequency. Oscillatory control inputs are employed to demonstrate the differences in... Topics: COLLISION AVOIDANCE, PREVENTION, HAZARDS, SYSTEMS ENGINEERING, RUNWAYS, PRIORITIES, MESSAGES,...
The occurrence of flight delays in Brazil, mostly verified at the ground (airfield), is responsible for serious disruptions at the airport level but also for the unchaining of problems in all the airport system, affecting also the airspace. The present study develops an analysis of delay and travel times at Sao Paulo International Airport/ Guarulhos (AISP/GRU) airfield based on simulation model. Different airport physical and operational scenarios had been analyzed by means of simulation.... Topics: SYSTEMS SIMULATION, SOFTWARE ENGINEERING, SYSTEMS ENGINEERING, FORMALISM, ARCHITECTURE (COMPUTERS)
The vast majority of satellites and near-earth probes developed to date have relied upon photovoltaic power generation. If future missions to probe environments close to the sun will be able to use photovoltaic power, solar cells that can function at high temperatures, under high light intensity, and high radiation conditions must be developed. For example, the equilibrium temperature of a Mercury surface station will be about 450 C, and the temperature of solar arrays on the proposed ''Solar... Topics: RADIATION BELTS, TRAPPED PARTICLES, SYSTEMS ENGINEERING, SPACECRAFT MODELS, STANDARDS
byCarati, Daniele; Rogers, Michael M.; Wray, Alan A
A statistical ensemble of large eddy simulations (LES) is run simultaneously for the same flow. The information provided by the different large scale velocity fields is used to propose an ensemble averaged version of the dynamic model. This produces local model parameters that only depend on the statistical properties of the flow. An important property of the ensemble averaged dynamic procedure is that it does not require any spatial averaging and can thus be used in fully inhomogeneous flows.... Topics: PROJECT MANAGEMENT, LEARNING, TEAMS, HUMAN PERFORMANCE, SYSTEMS ENGINEERING
A NUMBER OF FACTORS, INCLUDING INDICES OF THE VALUE (SCIENTIFIC, APPLIED, METHODOLOGICAL), LEVEL OF INTRODUCTION (PUBLICATION, MATERIALS AND EQUIPMENT, CREATIVE PROBLEM SOLVING), AND LEVEL OF IMPORTANCE ARE CONSIDERED TO BE MAJOR FACTORS IN EVALUATING EFFICIENCY OF SCIENTIFIC RESEARCH. AN ANALYTICAL PARAMETRIC SYSTEM FOR QUANTITATIVE EVALUATION OF EFFICIENCY OF SCIENTIFIC RESEARCH IS PRESENTED. A SERIES OF CRITERIA FOR ASSIGNING A NUMERICAL RATING TO EACH PARAMETER AND A SET OF WEIGHTING... Topics: CHANNELS (DATA TRANSMISSION), OPTICAL COMMUNICATION, SIMULATORS, MODULATION, SCINTILLATION, SYSTEMS...
In the prototypical accident report, specific findings, particularly those related to causes and contributing factors, are usually written out explicitly and clearly. Also, the evidence upon which these findings are based is typically explained in detail. Often lacking, however, is any explicit discussion, description, or depiction of the arguments that connect the findings and the evidence. That is, the reports do not make clear why the investigators believe that the specific evidence they... Topics: AUTONOMY, SYSTEMS ENGINEERING, SPACE EXPLORATION, PROVING, NASA SPACE PROGRAMS
A wind tunnel investigation was made of the aerodynamic characteristics of a 14.5 foot semispan, externally-blown jet flap model. The model was equipped with a single 30-inch diameter, ducted fan with a 1.03 pressure ratio. The effects of flap size, fan vertical location, and wing sweep on the longitudinal aerodynamic characteristics were studied. Topics: ELECTRIC GENERATORS, HEAT EXCHANGERS, SNAP 8, COMPUTER PROGRAMS, SYSTEMS ENGINEERING
In this report, advanced scatterometer concept options to operate in the post-SeaWinds era are examined. In order to meet the future requirements of scientific and operational users, a variety of scatterometer systems capable of producing improved wind vector products are evaluated. Special emphasis is placed on addressing concept options that operate at higher altitudes in order to improve the temporal revisit time. A preliminary set of generalized wind measurement goals designed to meet the... Topics: SYSTEMS ENGINEERING, MICROELECTRONICS, MANAGEMENT SYSTEMS, COMPUTER TECHNIQUES, SECURITY,...
Spacecraft in orbit near libration point L1 in the Sun-Earth system are excellent platforms for research concerning solar effects on the terrestrial environment. One spacecraft mission launched in 1978 used an L1 orbit for nearly 4 years, and future L1 orbital missions are also being planned. Orbit determination and station-keeping are, however, required for these orbits. In particular, orbit determination error analysis may be used to compute the state uncertainty after a predetermined... Topics: SPACECRAFT, SYSTEMS ENGINEERING, FLIGHT MANAGEMENT SYSTEMS, MANNED SPACE FLIGHT, OPTIMIZATION
The results of the booster verification wind tunnel test are presented. These tests were conducted in a 14 x 14-inch trisonic wind tunnel utilizing a .0035 scale model. The nominal Mach numbers tested were 0.6, 0.9, 0.95, 1.0, 1.05, 1.20, 1.50, 2.0, 2.74, 3.00, 4.50 and 5.0. The angle of attack range was 5 to 40 deg. The yaw data was obtained over a range of -10 to 10 deg at fixed angles of attack of 0, 6, 15, 25, and 30 deg. The Reynolds number range was 4.2 to 6.9 million per foot. Results... Topics: LASERS, SPECTROSCOPIC ANALYSIS, SYSTEMS ENGINEERING, EMISSION SPECTRA, METALLURGY, RAMAN...